Message-ID: <000b01bf8292$5ba46600$d66b1b3f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: Modified MS20001P hinge
Date: Tue, 29 Feb 2000 00:52:18 -0800
Mime-Version: 1.0

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In regards to Angier's question concerning the above subject. (BTW, this
subject was covered extensively about a year ago).

After the first 200 - 250 hours on N235SP (an early 235) what I would call
excessive wear was noted in several hinges. This shows itself as black
streaks on the adjacent surface directly behind the hinge. Close examination
revealed that the aluminum was wearing in the hinge-pin loops and the black
stuff was the aluminum wear debris. The wear was most prevalent on the
outboard elevator and inboard main gear door hinges though some wear was
detected in the left aileron outboard hinge as well. In fact, the elevator
and gear door hinges were getting downright sloppy!

I purchased a kit from a gentleman (can't remember the name - help me out
here if anybody does) who supplies enough of the correct size Teflon tubing
and SS wire to retrofit an entire two place Lancair. It's a bit of a chore
to install but I am firmly convinced that it's worth the money and the
effort! My controls always operated quite smoothly but with the Teflon
covered hinge pin installed, they got even better!

Notably, there will always be some small amount of clearance in the standard
hinge/hinge-pin fit, which will allow airframe vibration (you are using a
reciprocating engine, aren't you?) to knock the parts together, causing some
wear in time. With the Teflon encased hinge-pin, there is no metal-to-metal
contact, hence no mechanism for vibration induced wear. In the ensuing 250
hours plus since installing mine, I have not seen any wear at all.

IMHO, there is no strength problem associated with using the slightly
smaller wire diameter as all the forces are presented to the wire in shear
right at the separations between the opposing hinges. I believe you'd tear
the hinge out of the surface before the hinge wire failed.

Cheers,

Dan Schaefer

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